Perhaps the most important event in UFC history takes place tonight, as the world's premiere mixed-martial arts organization makes its network debut on FOX. The event airs at 9 PM ET, and features a huge UFC heavyweight title fight between champion Cain Velasquez and challenger Junior Dos Santos. This is Velasquez's first title defense since destroying former WWE Champion Brock Lesnar at UFC 121 last year to win the strap. You can check out that fight above.

If you've never watched the UFC, or have only seen a handful of events in the past, I would strongly suggest checking this one out. It airs for FREE on FOX, and will take place before the Juan Manuel Marquez - Manny Pacquiao fight later tonight.

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